URDF model created by Erwin Coumans.
Meshes derived from Laikago cad model, used by permission of Unitree.

If you use the model, add a citation to PyBullet:

@MISC{coumans2018,
author =   {Erwin Coumans and Yunfei Bai},
title =    {PyBullet, a Python module for physics simulation for games, robotics and machine learning},
howpublished = {\url{http://pybullet.org}},
year = {2016--2018}
}